I'm from the new age. I don't really care if they did it differently in the 1990s.
The second part isn't a good example at all. And while I agree where a set play starts and ends is fluid and up for debate I also think that ending it the second someone touches it after the corner or free kick very much misses the point of classifying it as something different than standard play. When I say not my consensus what I mean is the places that count things like set play goals categorically do not view it that way.
It's like a free-kick: you can score a free-kick or from a free-kick; they are not mutually one and the same. The first, it's a dead ball situation - a clear definition.
The latter, the ball comes into play and players attack the ball. Statistically, they're not defined the same. If I head a free-kick in, I've not scored a free-kick have I?
Would it be marked in any specific way apart from a header? No, because it was in open play. It was like that 20 years ago and this morning when I played.